   "Set up the attributes the first layer in a sweep needs in order to serve
   as a basis for ordering the following layer"
   [graph seed-order]
-  (let [layer (-> graph
-                  :layers
+  (let [layer (-> graph :layers
                   (get 0)
                   (assoc :flat seed-order :ordered seed-order))]
-    (-> graph
-        (assoc-in [:layers 0] layer)
+    (-> (assoc-in graph [:layers 0] layer)
         (neighborify layer)
         (indexify layer))))
 

                             #{}))
                  g (update-in graph [:marked] set/union marked)]
              (recur g tree parent-index c))
            (let [t (-> tree
                        (update-in [real-right-index :weight] + weight)
                        (cond->
                         is-seg-c (assoc-in [real-right-index :is-seg-c] true)
                         (not is-seg-c) (update-in [real-right-index :node-edges]

  from last-node to r node"
  (let [r-layer-id (inc (:layer-id last-node))
        [r-g r-node] (make-node graph r-layer-id {:characters characters})
        g (-> (update-in r-g [:rs] conj r-node)
              (add-edge last-node r-node characters))]
    [g r-node]))

